A humidity control apparatus using a so-called “desiccant rotor” and a heat pump in combination with each other has been known in the art, as disclosed in Japanese Laid-Open Patent Publication No. 9-329371. In such a humidity control apparatus, the condenser of the heat pump is provided along the air passageway for regeneration, and the evaporator of the heat pump is provided along the supply air passageway for supplying the air into the room. The humidity control apparatus performs an operation of dehumidifying the supply air for ventilation through the desiccant rotor and supplying the air into the room while regenerating the desiccant rotor with the discharge air for ventilation.
Specifically, the outside air is taken into the humidity control apparatus as the supply air for ventilation. The outside air is dehumidified through the desiccant rotor and then flows into the supply air passageway. Then, the air is cooled by heat exchange with the refrigerant through the evaporator, and then supplied into the room. Moreover, the room air is taken into the humidity control apparatus as the discharge air for ventilation. The room air is heated by heat exchange with the refrigerant through the condenser while flowing along the air passageway for regeneration. Then, the air is used for the regeneration of the desiccant rotor, after which it is discharged to the outside.
Problems to be Solved
However, the conventional humidity control apparatus described above has a configuration that is made only in view of the dehumidification mode for dehumidifying the air to be supplied into the room, and cannot provide a sufficient capacity when it is used in the humidification mode for humidifying the air to be supplied into the room.
In order to perform a humidification mode operation, it is necessary that an air humidified with the moisture desorbed from the desiccant rotor is passed into the supply air passageway. In the humidity control apparatus, however, the evaporator of the heat pump is provided along the supply air passageway. Therefore, the humidified supply air is cooled through the evaporator, where a portion of the moisture contained in the air is condensed. Thus, with the humidity control apparatus, the moisture contained in the supply air is reduced as the supply air passes through the evaporator, failing to provide a sufficient humidification capacity.
The present invention has been made in view of the above, and has an object to provide a humidity control apparatus having a refrigerant circuit with which it is possible to obtain a sufficient humidification capacity.